How to calculate percentages
A percentage is a fraction whose denominator (bottom number) is always 100. It is denoted using the percent sign (%) or the abbreviations pct. So 1% is 1/100. If we say 20%, we mean 20/100 = 1/5. So 25% means 1/4 and 50% means 1/2
If you have to turn a percentage into a decimal, just divide by 100. For example, 25% = 25/100 = 0.25
If you have to turn a percentage into a fraction, just add 100 as a denominator. For example, 50% = 50/100 = 1/2
The following examples show how to calculate percentages:
3 is what percent of 12?
What is 20% of 80?
8 is 40% percent of what number?
The price of a book was increased from 10 to 12 USD. Express this increase as a percentage change of the original price.
The price of a book was decreased from 15 to 10 USD. By what percentage did it decrease?